1. Field of the Invention
The present invention relates to a network application decentralized execution system wherein a network application developed for a centralized switched network can be applied to a decentralized switched network.
2. Description of the Related Art
A system which provides an application programming interface (API) which abstracts and utilizes network controlling functions of a switching system is called open API of a network and serves as a platform for providing network service applications which make use of intra-network communication resources such as a switched network, a media storage and synthesis trunk and a multi-point conference control trunk.
Recently, such corporate bodies as the JAIN and the Parlay which standardize a set of such APIs as mentioned above have been organized, and a network application developed based on an API standardized by any of such corporate bodies can be utilized commonly between various switching systems of different implementation forms for which the API is ready. Thus, such network applications are generally useful for reduction of the period of development of a network application.
An interface between execution environments of an application described in an existing network API such as the JAIN or the Parlay and a switching system is conventionally implemented by connection between a server which executes the application and a control apparatus in an exchange. This makes it possible to perform detection of an event and a controlling operation from the application in response to a connection call managed in the control apparatus in the exchange.
The API set includes seven APIs given below in accordance with individual functions:
1. Event collection type API
2. State collection type API
3. Connection destination control type API
4. User interaction type API
5. Database accessing type API
6. Process calling type API
7. Process ending type API
A network application can be constructed by a suitable combination of the APIs given above.
Meanwhile, a voice over Internet protocol (VoIP) network which is a switching service network in which the Internet protocol is used has been constructed recently, and the architecture for switched network control has begun to vary fundamentally.
In the VoIP network, each terminal equipment has a call state holding function and a mutual connection function incorporated therein so that it can establish a connection directly to another terminal equipment of the other party without intervention of an exchange using connection destination address information acquired from a directory server.
Such decentralized connection control as just described can significantly reduce the load to a server necessary for a switching network service.
However, a function module corresponding to the control apparatus of an exchange which is a destination of connection of a network application described above is decentralized and eliminated. In particular, communication in decentralized connection control is performed without intervention of an exchange, and therefore, application execution environments (refer to description hereinafter given with reference to FIG. 7) cannot control communication. Therefore, there is a problem that a network application developed for a centralized switched network cannot be applied to a decentralized switched network.